Haggai is counted among the Twelve Minor Prophets of the Old Testament, traditionally listed as the tenth of their number. According to the Orthodox synaxarion he was of the Tribe of Levi and descended from Aaron. He belongs to the generation of the return from the Babylonian Captivity and, by the reckoning of the biblical book that bears his name, prophesied during the reign of the Persian emperor Darius Hystaspis, with his recorded messages falling in a single year placed in the late sixth century B.C.
Haggai's principal mission was to rouse the returned exiles to complete the rebuilding of the Temple at Jerusalem, the so-called Second Temple, after the work had been interrupted. The synaxarion records that he persuaded the people to undertake the construction, and the biblical account associates his preaching with the leadership of the governor Zerubbabel and the high priest Joshua. He labored in the same period as the Prophet Zechariah, who is likewise numbered among the Twelve and is associated with the same restoration of the Temple.
The book attributed to Haggai also preserves a prophecy concerning the future glory of the rebuilt house, which Orthodox tradition reads as a foretelling that the Messiah would appear in this Temple in the last times. After his prophetic ministry it is believed that Haggai was buried at Jerusalem among the priests. He is commemorated by the Orthodox Church on December 16.